https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114533
--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> --- I guess we should go with the above patch after fixing formatting, but it isn't enough, printf_fphex.c has similar code. Even in glibc which doesn't support printing _Float128 nor any other type which would require similar alignment, the hooks only register a function to fill in some mem and allows specification of size, but can't specify alignment.
